1. Field of the Invention
The present invention relates to a method for producing a photochromic comprising a composite oxide that changes its light transmittance by UV irradiation, and a method for producing a photochromic material. In particular, the present invention relates to a photochromic suitable for printing materials, optical instruments, recording materials, display materials, dimming materials, photosensitive elements, clothes and ornaments.
2. Description of the Related Art
Organic materials such as chromene photochromic materials have been known in the art as materials that changes their light transmission property by irradiating light.
Although organic materials such as the chromene photochromic materials become opaque by several seconds of light irradiation, and return to a transparent state within several seconds to several minutes by leaving it in a dark place, it has been a problem that a stable light transmission property cannot be obtained once the material has become opaque by light irradiation.